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{* UltraStar Deluxe - Karaoke Game
*
* UltraStar Deluxe is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*}
unit UConsole;
interface
{$IFDEF FPC}
{$MODE Delphi}
{$ENDIF}
{$DEFINE SYNCHRONIZE_CONSOLE}
procedure ConsoleWriteLn(const msg: string);
implementation
uses
// Do not include the unit 'Libc', it also defines TRTLCriticalSection,
// use the TRTLCriticalSection
{$IFDEF MSWINDOWS}
Windows,
{$ENDIF}
SysUtils,
SyncObjs,
Classes;
procedure _ConsoleWriteLn(const aString: string); {$IFDEF HasInline}inline;{$ENDIF} forward;
{$IFDEF SYNCHRONIZE_CONSOLE}
type
{**
* FPC uses threadvars (TLS) managed by FPC for console output locking.
* Using WriteLn() from external threads (like in SDL callbacks)
* will crash the program as those threadvars have never been initialized.
* Access to the console by two non-managed threads in Delphi also causes a
* crash.
*
* The solution is to create an FPC/Delphi-managed thread which has the TLS data
* and use it to handle the console-output (hence it is called Console-Handler)
* This must be a thread managed by FPC/Delphi, otherwise (e.g. SDL-thread)
* it will crash when using Writeln.
*}
TConsoleHandler = class(TThread)
private
fMessageList: TStringList;
fConsoleCriticalSection: TCriticalSection;
fConsoleEvent: TEvent;
public
constructor Create();
destructor Destroy(); override;
procedure WriteLn(const msg: string);
protected
procedure Execute(); override;
end;
var
ConsoleHandler: TConsoleHandler;
constructor TConsoleHandler.Create();
begin
inherited Create(false);
// init thread-safe output
fMessageList := TStringList.Create();
fConsoleCriticalSection := TCriticalSection.Create;
fConsoleEvent := TEvent.Create(nil, false, false, 'ConsoleEvent');
end;
destructor TConsoleHandler.Destroy();
begin
// terminate console-handler
fConsoleCriticalSection.Enter;
Terminate;
fConsoleEvent.SetEvent();
fConsoleCriticalSection.Leave();
WaitFor();
// free data
fConsoleCriticalSection.Free;
fConsoleEvent.Free;
fMessageList.Free;
inherited;
end;
{*
* The console-handlers main-function.
*}
procedure TConsoleHandler.Execute();
var
i: integer;
begin
while (true) do
begin
// wait for new output or quit-request
fConsoleEvent.WaitFor(INFINITE);
fConsoleCriticalSection.Enter;
try
// output pending messages
for i := 0 to fMessageList.Count - 1 do
begin
_ConsoleWriteLn(fMessageList[i]);
end;
fMessageList.Clear();
// use local quit-variable to avoid accessing
// ConsoleQuit outside of the critical section
if (Terminated) then
Break;
finally
fConsoleEvent.ResetEvent();
fConsoleCriticalSection.Leave;
end;
end;
end;
procedure TConsoleHandler.WriteLn(const msg: string);
begin
// TODO: check for the main-thread and use a simple _ConsoleWriteLn() then?
//GetCurrentThreadThreadId();
fConsoleCriticalSection.Enter;
try
fMessageList.Add(msg);
fConsoleEvent.SetEvent();
finally
fConsoleCriticalSection.Leave;
end;
end;
{$ENDIF}
(*
* Write to console if one is available.
* It checks if a console is available before output so it will not
* crash on windows if none is available.
* Do not use this function directly because it is not thread-safe,
* use ConsoleWriteLn() instead.
*)
procedure _ConsoleWriteLn(const aString: string); {$IFDEF HasInline}inline;{$ENDIF}
begin
{$IFDEF MSWINDOWS}
// sanity check to avoid crashes with writeln()
if (IsConsole) then
begin
{$ENDIF}
Writeln(aString);
{$IFDEF MSWINDOWS}
end;
{$ENDIF}
end;
procedure ConsoleWriteLn(const msg: string);
begin
{$IFDEF CONSOLE}
{$IFDEF SYNCHRONIZE_CONSOLE}
ConsoleHandler.WriteLn(msg);
{$ELSE}
_ConsoleWriteLn(msg);
{$ENDIF}
{$ENDIF}
end;
procedure InitConsoleOutput();
begin
{$IFDEF SYNCHRONIZE_CONSOLE}
ConsoleHandler := TConsoleHandler.Create;
{$ENDIF}
end;
procedure FinalizeConsoleOutput();
begin
{$IFDEF SYNCHRONIZE_CONSOLE}
ConsoleHandler.Free;
{$ENDIF}
end;
initialization
InitConsoleOutput();
finalization
FinalizeConsoleOutput();
end.
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